Drill bit nozzle

Abstract

A drill bit for connection on a drill string has a hollow tubular body with an end cutting face and an exterior peripheral stabilizer surface with cylindrical sintered carbide inserts positioned therein and a novel arrangement for securing replaceable nozzles. Nozzle passages extend from the interior of the bit body through the cutting face for receiving a removable and interchangeable nozzle member therein. A portion of the length of each passage is threaded and the remainder of the passage is enlarged and of a smooth bore. The nozzle member is formed of wear-resistant hard metal, e.g. carbide, and has a metal sleeve brazed thereon with male threads operable to be fitted in the threads in said nozzle passage. The nozzle member is threadedly secured in place during installation and optionally further secured against unscrewing and additionally protected against wear or erosion by a metal or hard metal, e.g. carbide, retaining ring having an interference fit in the smooth portion of the nozzle passage. The shape of the hard metal nozzle member protects the entire nozzle assembly, and particularly the threaded metal sleeve, from erosion produced by abrasive drilling fluids. The cutting face supports suitable cutting means, preferably diamond cutting elements. The replaceable nozzles with threaded exteriors and protecting retaining rings may be used with other types of drill bits, e.g. roller cone bits, but are particularly useful with diamond bits because of the close proximity of the nozzles to the cutting surface in diamond bits which results in a very high wear rate.

I claim: 
     
       1. A drill bit with replaceable nozzles comprising a drill body having a hollow tubular body adapted to be connected to a drill string,   said drill body having an exterior peripheral stabilizer surface and an end cutting face,   a plurality of cutting elements supported in cutting position in said cutting face,   at least one nozzle passage in said drill body comprising a passage opening from the interior of said body and a first counterbore aligned therewith to form a shoulder therein and internally threaded for at least a portion of its length and a second counterbore having a smooth cylindrical wall extending from said first counterbore and opening through said cutting face adjacent to said cutting elements,   a removable nozzle member of abrasive resistant hard metal, having a cylindrical external surface, and an enlarged cylindrical end flange,   said nozzle member cylindrical surface being of a size fitting inside said first counterbore and said cylindrical end flange fitting tightly in said second counterbore,   a metal sleeve secured on said nozzle member cylindrical surface and having male threads formed therein sized to fit said first counterbore threaded portion, and   said nozzle member being threadedly secured in said counterbore threaded portion with the end portion thereof fitting in said counterbore against said shoulder and said cylindrical end flange tightly fitted inside the end of said second counterbore to protect said threaded metal sleeve from abrasive wear.   
     
     
       2. A drill bit according to claim 1 in which said threaded sleeve is brazed on said cylindrical surface of said nozzle member.   
     
     
       3. A drill bit according to claim 2 in which said nozzle member has a flanged end portion shaped to receive a tool to turn the same for insertion or removal, and   said flanged end portion shielding said metal sleeve threads against abrasive wear during use.   
     
     
       4. A drill bit according to claim 3 in which said flanged end portion has recesses or indentations in the end face thereof for receiving a tool.   
     
     
       5. A drill bit according to claim 2 in which said threaded sleeve is of steel.   
     
     
       6. A drill bit according to claim 1 including an annular metal or hard metal retaining ring having an exterior surface slightly larger than the unthreaded portion of said counterbore adjacent to said cutting surface and fitted in said counterbore by an interference fit against the end of said nozzle member to protect said nozzle member against unscrewing.   
     
     
       7. A drill bit according to claim 6 in which said retaining ring is of a hard steel.   
     
     
       8. A drill bit according to claim 6 in which said retaining ring is of hard metal.   
     
     
       9. A drill bit according to claim 6 in which said retaining ring has a cylindrical external surface, flat end surfaces, and an internal opening having a conical surface flaring outward toward the surface of said cutting face.   
     
     
       10. A drill bit according to claim 6 in which said retaining ring is recessed from the opening of said counterbore through said cutting face.   
     
     
       11. A drill bit according to claim 1, in which said drill body has a plurality of said passages and counterbores, and   a plurality of said nozzle members positioned one in each of said counterbores.   
     
     
       12. A drill bit according to claim 1 in which said counterbore has an internal circumferential groove surrounding said nozzle member adjacent to said shoulder, and   an elastomeric O-ring surrounding said nozzle member and positioned in said groove.   
     
     
       13. A drill bit according to claim 1 in which said cutting face comprises a crown surface defined by the intersection of an outer conical surface and an inner negative conical surface, and   said counterbore opens through said crown surface.   
     
     
       14. A drill bit according to claim 1 in which said cutting face has a plurality of cylindrical recesses spaced therearound in a selected pattern,   a plurality of cutting elements, one for each of said recesses,   said cutting elements each comprising a cylindrical supporting stud of sintered carbide having an angularly oriented supporting surface wit a disc shaped element bonded thereon comprising a sintered carbide disc having a cutting surface comprising polycrystalline diamond,   each of said cutting elements being positioned in one of said recesses by an interference fit, and   said counterbore opening through said cutting face adjacent to selected ones of said cutting elements.   
     
     
       15. A drill bit with replaceable nozzles comprising a drill body having a hollow tubular body with an end wall at one end and adapted to be connected at the other end to a drill string,   said drill body having cutter means supported thereon,   at least one nozzle passage in said drill body comprising a passage opening from the interior of said body and a first counterbore aligned therewith to form a shoulder therein and internally threaded for at least a portion of its length and a second counterbore having a smooth cylindrical wall extending from said first counterbore and opening through said end wall adjacent to said cutter means,   a removable nozzle member of abrasive resistant hard metal, having a cylindrical external surface, and an enlarged cylindrical end flange,   said nozzle member cylindrical surface being of a size fitting inside said first counterbore and said cylindrical end flange fitting tightly in said second counterbore,   a metal sleeve secured on said nozzle member cylindrical surface and having male threads formed therein sized to fit said first counterbore threaded portion, and   said nozzle member being threadedly secured in said counterbore threaded portion with the end portion thereof fitting in said counterbore against said shoulder and said cylindrical end flange tightly fitted inside the end of said second counterbore to protect said threaded metal sleeve from abrasive wear.   
     
     
       16. A drill bit according to claim 15 including additionally an annular metal or hard metal retaining ring having an exterior surface slightly larger than said counterbore and fitted in said counterbore by an interference fit against the end of said nozzle member to retain said nozzle member in position and protect it against unscrewing.   
     
     
       17. A removable nozzle member for use in earth drilling bits or other tools, comprising a body portion formed of hard metal, selected from the group consisting of metal carbides, oxides, borides, nitrides and silicides, having a cylindrical exterior surface and an internal nozzle shaped passage extending longitudinally thereof,   a metal sleeve secured on said cylindrical surface and having male threads formed in the exterior surface thereof adapted to be secured in a threaded passage in a drill bit, and   an enlarged cylindrical end flange at an end of said body portion away from said threaded sleeve,   said threaded sleeve being adapted to be secured in a threaded opening in a metal body and said cylindrical flange being adapted to fit a counterbore in a metal body in sealing relation thereto and protecting said threaded sleeve portion against abrasive wear.   
     
     
       18. A nozzle member according to claim 17 in which said threaded sleeve is brazed on said cylindrical surface of said nozzle member. 
     
     
       19. A nozzle member according to claim 18 in which said nozzle member flanged end portion has an end surface shaped to receive a tool to turn the same for insertion or removal.   
     
     
       20. A nozzle member according to claim 19 in which said flanged end portion has recesses or indentations in the end face thereof for receiving a tool.   
     
     
       21. A nozzle member according to claim 18 in which said threaded sleeve is of steel.   
     
     
       22. An apparatus with a replaceable nozzle comprising a metal body having at least one nozzle passage therein comprising a passage opening therethrough and a first counterbore aligned therewith to form a shoulder therein and internally threaded for at least a portion of it length and a second counterbore having a smooth cylindrical wall extending from said first counterbore,   a removable nozzle member of abrasive resistant hard metal, having a cylindrical external surface, and an enlarged cylindrical end flange,   said nozzle member cylindrical surface being of a size fitting inside said first counterbore and said cylindrical end flange fitting tightly in said second counterbore,   a metal sleeve secured on said nozzle member cylindrical surface and having male threads formed therein sized to fit said first counterbore threaded portion, and   said nozzle member being threadedly secured in said counterbore threaded portion with the end portion thereof fitting in said counterbore against said shoulder and said cylindrical end flange tightly fitted inside the end of said second counterbore to protect said threaded metal sleeve from abrasive wear.